FIG. 1 diagrammatically shows a by-pass turbine engine for aeronautical propulsion. It comprises a fan 10 creating an air stream of which the central part, called the core engine flow Fp or primary flow, is injected into a, compressor 12 that feeds a turbine 14 that drives the fan.
The peripheral part of the air stream called the fan flow Fs, or secondary flow, is released into the atmosphere to supply part of the thrust of the turbine engine 1 after passing through a ring of fixed blades arranged downstream from the fan. This ring called the Outlet Guide Vanes (OGVs) 20 guides the air flow at the outlet from the fan while minimising losses. A reduction of 0.1% of losses (for example pressure reduction) in the outlet guide vane can increase the overall efficiency of the fan and outlet guide vane assembly by 0.2 points, the correspondence between losses and efficiency obviously depending on the engine and the aerodynamic load of the associated fan.
Consequently, the air flow in the flow stream through the outlet guide vane should be optimised and losses should be minimised.
The vanes of the outlet guide vane 20 are fixed onto a hub 30 by means of bolts. FIG. 2 shows a sectional view of a vane root of an outlet guide vane at its attachment to the hub 30 of the turbine engine. As shown, the vane root comprises attachment orifices 22 that mechanically connect the vane to the hub 30 through screwing system 23. The attachment orifices 22 are formed from a first through reaming 22a and from a second blind reaming 22b with a larger diameter, opening up at the upper face of the root, the diameter of which is adapted to allow the head 24 of the screwing system 23 to pass through. A ring or a cup 25 may be placed in the blind reaming 22b between the screwing system 23 and the root 21 to prevent hammering or marking of parts.
These reamings create stop faces for the air flow causing aerodynamic turbulence of the air flow in the outlet guide vane air stream.
To overcome this problem, it has been proposed to fill in these reamings (once the vane is in position) using a silicone-based compound known as RTV (Room Temperature Vulcanizing) silicone to eliminate all stop faces in the guide vane flow stream and particularly at the vane roots.
Use of this silicone-based compound requires a long drying time and consequently increases the duration of assembly operations. The use of silicone for filling the attachment orifices also increases the disassembly time, particularly during maintenance operations because the compound has to be removed and orifices have to be cleaned before reassembly.